‘Honeycrisp’ Bitter Pit Response to Rootstock and Region under Eastern New York Climatic Conditions

Abstract

There are still unknown factors at play in the causation of bitter pit in ‘Honeycrisp’ as well as in other apple varieties. To investigate some of these factors, we conducted a survey of 34 ‘Honeycrisp’ orchard blocks distributed across two disparate production regions in eastern New York State, representing a variety of rootstocks, over three growing seasons. Weather, soil, horticultural traits, fruit quality traits, pick timing, leaf and peel minerals were evaluated for their impact on bitter pit (BP) incidence; factors were further evaluated for their interaction with region and rootstock. ‘Honeycrisp’ trees on B.9 rootstock were smaller but with comparable terminal shoot growth when compared to those on M.26 and M.9 rootstocks. B.9 fruits, which had similar fruit size to M.26 and M.9 and had good fruit quality at harvest and after storage, were much less likely to express bitter pit symptoms compared to M.9 and M.26 rootstocks. Not all traits evaluated individually correlated significatively with bitter pit incidence after a period in storage. Depending on rootstock and region, the correlation could be significant in one situation, with no correlation at all in another. In this study, peel Mg/Ca ratio and peel Ca correlated with BP for all three rootstocks, with the strongest correlations associated with the M.9 clones. These same traits correlated with BP for both regions. Pick timing had a significant influence on BP incidence following storage, with later picks offering better bitter pit storage performance. While excessively large fruits, those in the 48 and 56 count size categories, were found to be highly susceptible to BP regardless of rootstock, B.9 BP fruit susceptibility for smaller sizes was found to be size neutral. A PLSR prediction model for each rootstock and each region showed that different variables correlated to BP depending on the situation. Thus, the results could suggest that in addition to the variables considered in this study, there are other less studied factors that can influence the expression of BP symptoms. We strongly suggest that rootstock BP performance be considered a critical parameter when planning a commercial ‘Honeycrisp’ orchard and be evaluated in rootstock breeding and development programs prior to wide commercial release.

Rootstock and Nutrient Imbalance Leads to ‘‘Green Spot’’ Development in ‘WA 38’ Apples

“…The relation between fruit size and Ca-related physiological disorders is debatable, whereas many studies have shown a positive relation between BP and larger fruit size (Fallahi et al, 1985;Perring and Jackson, 1975;Reid and Kalcsits, 2020;Valverdi and Kalcsits, 2021), several others have not found a direct correlation (Amarante et al, 2020;Donahue et al, 2021;Ferguson and Watkins, 1992). Recently, Donahue et al (2021) suggested that the relation with fruit size and BP occurs only with exceptionally large fruit, in 'Honeycrisp' with 48 to 56 size box (equivalent to >89 mm fruit and 340 g fruit), below which threshold there is no correlation. Fruit load, in the current trial, had a strong negative correlation with GS incidence (y 5 À0.0078x 1 0.88, R 2 5 0.662, R 5 À0.814, P < 0.0001) (Fig.…”

“…In this study, in 2018, fruit size was 15% higher on 'M.9', which actually had reduced GS levels compared with 'G.41'. However, the role of fruit size has been debated as a factor associated with BP and other Carelated disorders (Donahue et al, 2021;Ferguson and Watkins, 1992). Crop load, on the other hand, has more widely been suggested as an important factor associated with Ca-related disorders and nutrient balance in apples (Ernani et al, 2008;Ferguson and Watkins, 1992;Robinson and Watkins, 2003;Serra et al, 2016;Volz et al, 1993).…”

Effects of Different Crop Loads on Physiological, Yield and Fruit Quality of ‘JoyaTM’ Apple Trees: High Crop Load Decreases Maximum Daily Trunk Diameter and Does Not Affect Stem Water Potential

“…Rootstocks can affect fruit nutrient composition and bitter pit susceptibility by affecting the nutrient absorption and distribution of trees (Fazio et al, 2020;Reig et al, 2018;Valverdi and Kalcsits, 2021). Donahue et al (2021) found no direct relationship between crop load and bitter pit incidence, and rootstock and climatic conditions were influential in the rate of bitter pit incidence.…”

Rootstock effects on bitter pit incidence in ‘Honeycrisp’ apples are associated with changes in fruit’s cell wall chemical properties

“…‘Honeycrisp’ is the third most-produced apple cultivar in the USA, after ‘Gala’ and ‘Red Delicious’ ( Donahue et al., 2021 ). The high market value and consumer demand for this variety is largely due to its unique fruit quality characteristics (juicy, crispy, and strong-flavored) and palatability at harvest, which are sustained during storage ( Al Shoffe et al., 2020 ).…”

“…Rootstock’s influence on BP was explained in light of rootstock differences in the absorption and transport of certain nutrients, which in turn affect the composition of the scion’s levels of K + , Mg 2+ and Ca 2+ . For instance, in a study conducted by Donahue et al., 2021 , the authors studied the effects of three rootstocks, M.9, M.26 and B.9 on BP incidence in ‘Honeycrisp’ apples and revealed that the peel Mg 2+ /Ca 2+ ratio and peel Ca 2+ level could be a good indicator of BP incidence. In a separate study, using a more genetically-diverse group of apple rootstocks, Fazio et al., 2020 , showed that rootstocks have a significant impact on the Ca 2+ , K + , and K + /Ca 2+ ratio in the scion tissues, and that K + /Ca 2+ in the leaves and fruit of the scion was tightly correlated with BP incidence.…”